Fluid handling devices are becoming increasingly popular and there is an increased demand for fluid handling devices that are both portable and easy to use. Portable fluid handling devices are being used for applications such as home care, point of care testing, fuel cells, fragrance dispensers, etc. In order for a portable fluid handling device to be effective and efficient, it should be light weight, small in size, consume minimal power, and be cost effective to manufacture. In many applications, it is also important that the fluid handling device provide an accurate and consistent fluid distribution. Therefore, it is necessary to incorporate an efficient fluid valve in the fluid handling device. In many aspects, the fluid valve characterizes the device's efficiency.
One solution of a portable valve that attempts to meet the above criteria is a miniature solenoid valve. The miniature solenoid valve however, is not as effective as originally anticipated. Solenoid valves are limited in both size as well as power consumption. In order to obtain adequate performance, a solenoid valve typically consumes a substantial amount of power. The power consumption of a solenoid valve, in some circumstances, is unacceptable when using batteries as a power source.
Another solution has been the use of electrically actuated piezo valves. Some piezo valves operate using a closing arm that seals against a sealing shoulder when the piezo element is de-activated. These valves typically require a substantial amount of space to operate and may not always provide an adequate solution as they are subject to clogging when used with liquids that may dry around the orifice. However, it is also known in the art to provide a sealing ball, which seals against a sealing shoulder.
For example, international patent application publication WO/2009/106233, which is assigned on its face to the present applicant and incorporated herein by reference, discloses an electrically actuated valve with a sealing ball. The valve includes a vibrating element and an amplifying plate in contact with the vibrating element.
FIG. 1 shows a simplified cross-sectional view of a prior art valve 10 similar to the valve shown in FIG. 3 of the '233 application. The prior art valve 10 includes a housing 11, which is separated into a first portion 11a and a second portion 11b. The first portion 11a includes a fluid inlet 12 while the second portion 11b includes a fluid outlet 13. As can be appreciated, the fluid inlet 12 can be adapted to receive a pressurized fluid from a pressurized fluid supply (not shown). Further, the fluid outlet 13 can be provided to deliver fluid to a desired component (not shown). The valve 10 is therefore, designed to control the flow of the pressurized fluid from the fluid inlet 12 to the fluid outlet 13.
The prior art valve 10 is also shown with electrical contacts 14. The electrical contacts 14 are in contact with electrodes 15 to supply power to a vibrating element 16. The vibrating element 16 may comprise a piezoelectric material as explained in the '233 application. The vibrating element 16 is capable of vibrating when energized, i.e., when exposed to an electrical field or an electric potential. Piezoelectric materials are known in the art and are often used for their physical characteristics when energized by an alternating field. If an alternating electric field is applied to the piezoelectric element, the element 16 changes dimensions at a frequency of the electric field. Therefore, the vibrating element 16 converts electrical energy into mechanical energy. The valve 10 further includes an amplifying plate 17. The amplifying plate 17 can transfer and amplify vibrations produced by the vibrating element 16 to a sealing ball 18. The amplifying plate 17 also defines a fluid passage 19 through which fluid can flow. The fluid acting on the amplifying plate 17 is prevented from reaching the vibrating element 16 by two sealing members 20a, 20b. 
The sealing ball 18 is sized and shaped to form a substantially fluid-tight seal with the fluid passage 19 to prevent fluid flow. As explained in the '233 application, the pressure of the fluid in the fluid chamber 21 provides the biasing force against the sealing ball 18. In order to allow fluid to flow through the valve 10, the vibrating element 16 is energized and caused to vibrate. The vibrations are transferred and possibly amplified by the amplifying plate 17. The vibrations of the amplifying plate 17 overcome the fluid pressure that forces the sealing ball 18 to seal against the fluid passage 19, thereby allowing fluid to flow between the inlet 12 and outlet 13.
While the prior art valve 10 provides suitable control for relatively low flow operations, as can be appreciated, the pressure of the fluid acts on a single side of the amplifying plate 17. More specifically, the pressure of the fluid acts on the inlet side of the amplifying plate 17 exposed to the inlet pressure chamber 21 across a diameter, D of the plate 17. The diameter D extends substantially entirely across the inlet pressure chamber 21. Consequently, the pressure of the fluid tends to dampen the vibrations of the amplifying plate 17. While the fluid damping may not be significant for some fluid pressures, as the fluid pressure increases, the power required to vibrate the amplifying plate 17 with predetermined amplitude also increases. As a result, high pressure applications may require an excessive amount of power.
The embodiments described below overcome this and other problems and an advance in the art is achieved. The embodiments provide an amplifying plate with one or more pressure balancing apertures. The apertures permit fluid at the inlet to act on both sides of at least a portion of the amplifying plate. The apertures can advantageously reduce the cross-sectional area of the amplifying plate that is exposed to pressurized fluid on a single side. With fluid acting on both sides of the amplifying plate, fluid dampening of the amplifying plate is substantially reduced.